Cops mistakenly trashed a deadly DWI driver’s car, leading to a sweetheart deal for the reckless motorist, officials revealed today.

Adam Greenberg, 34, was sentenced to two years to six years in prison by Manhattan Supreme Court Justice Michael Obus, in exchange for the defendant copping to aggravated vehicular manslaughter, vehicular assault, DWI and assault.

Prosecutors admitted they would have sought more time had workers at an NYPD impound lot not fouled up by shredding Greenberg’s car on July 28, 2009 — one day before defense experts were schedule to examine the Volkswagen Jetta.

Without the car, Greenberg was denied his chance to possibly cite mechanical failure for the deadly crash on July 21, 2008.

That’s when Greenberg, high on PCP, slammed into two motorcyclists — killing Dimitrios Kazanas, 39, and severely injuring Gary Quinlan, then 28 — near the Staten Island Ferry terminal.

Prosecutors asked that Greenberg be nailed for three years to nine years, but judge Obus said he had to follow through on his previous promise to the defendant two to six.

Greenberg’s vehicular manslaughter conviction could have landed him in prison for eight to 25 years. Prosecutors declined to speculate how much the car foul up weakened their hand.

An NYPD rep declined comment about the embarrassing error.

Greenberg seemed unfazed in the days immediately after the deadly crash. Cops confiscated his belongings — including his driver’s license — immediately after the accident.

Then four days later, Greenberg went to the DMV and had a new license issued, before department officials caught wind of his outrageous renewal and had his privileges revoked.

“My life has been changed forever,” said Quinlan, who no longer rides on cycles. “He [Greenberg] has shown no remorse or feeling for his actions.”

Still, Quinlan said he’s a lucky man for narrowly dodging death.

“Inches, it really was,” said Quinlan, standing next to his pregnant wife outside the court.